OBJECTIVETo characterize the clinical feature of a child with infantile spasm, karyotype and molecular cytogenetic analyses were performed to investigate the cause of disease and choose a suitable prenatal diagnostic method for the couple with the child.

METHODRoutine G-banding was performed to analyze the karyotype of the patient and her parents, and molecular karyotyping was performed using SNP array. Confirmation and segregation studies were performed by fluorescence in situ hybridization (FISH).

RESULTThe patient presented with severe psychomotor retardation, epilepsy, muscular hypotonia, stereotypic behavior and facial phenotype characterized by bulging forehead, cupid-bow upper lip, large ears with prominent lobes and pronounced occipital protuberance. Subdural collection of fluid was shown in cranial CT scan, and frequent interictal epileptiform discharges and hypsarrhythmia was shown in EEG monitoring. Routine G-banding revealed a normal female karyotype. A 2.03 Mb deletion in 5q14.3 including MEF2C gene was revealed using SNP array, and the patient's molecular karyotype was arr 5q14.3 (87 538 430-89 565 757) ×1. FISH with locus-specific probe RP11-293L20 from the deleted region on metaphase preparations of the patient and her parents confirmed the de novo occurrence of the deletion.

CONCLUSIONThe microdeletion of 5q14.3 was the cause of infantile spasm in the patient. FISH confirmed the de novo occurrence of the microdeletion. SNP array should be chosen as prenatal diagnostic method for the couple with the child.